The present disclosure relates to subject matter contained in priority Japanese Patent Application No. 2000-116382, filed on Apr. 18, 2000, the contents of which is herein expressly incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a prismatic battery and a method of manufacturing same.
2. Description of Related Art
For batteries having a prismatic shape, a structure may be adopted wherein rectangular positive and negative electrode plates are alternately stacked with intervening separators therebetween and collector plates of opposite polarities attached on the opposite sides of the group of electrode plates. After stacking the electrode plates upon one another, they must be tightly bundled together during the succeeding process steps so as to prevent any foreign substances from entering between the electrode plates. Particularly, molten metal particles are sputtered around the electrode plates during the welding of collector plates, and such conductive foreign substance causes short circuits across the positive and negative electrode plates.
In the past, the electrode plates, after being assembled into a group, had to be carefully inserted into a case so that the electrode plates will not be displaced, or that the active material coated on the electrode plates will not be scraped by the open end edge of the case.
In view of the problems encountered by the prior art, it is an object of the present invention to provide a prismatic battery and a manufacturing process for same, in which there is no risk that conductive foreign substances enter between stacked electrode plates.
To achieve the above-mentioned object, the present invention provides a prismatic battery, including a battery case for accommodating an electrode plate group and a liquid electrolyte therein. The electrode plate group includes a plurality of positive electrode plates and a plurality of negative electrode plates stacked alternately with intervening separators therebetween. The positive electrode plates and the negative electrode plates are laterally offset from each other so that side edges of the positive electrode plates protrude on one side and side edges of the negative electrode plates protrude on the other side of the electrode plate group. A first collector plate is joined perpendicularly to the side edges of the positive electrode plates on one side of the electrode plate group, and a second collector plate is joined perpendicularly to the side edges of the negative electrode plates on the other side of the electrode plate group. A tape is attached to part of the electrode plate group, at least bridging a loose end of an electrode plate positioned outermost of the electrode plate group and one of the first collector plate and the second collector plate.
The tape may be attached to the electrode plate group such as to stretch from the loose end of the outermost electrode plate on one side of the electrode plate group over one of the first and second collector plates to the loose end of the outermost electrode plate on the other side of the electrode plate group. Alternatively, the tape may be wound entirely around the electrode plate group to surround the outermost electrode plates and the collector plates.
A second tape may additionally be attached to the electrode plate group in the vicinity of the loose end of the outermost electrode plate, stretching from a bottom end of one outermost electrode plate over a bottom end face of the electrode plate group to a bottom end of the other outermost electrode plate.
Alternatively, a tape may be vertically wound around the electrode plate group in the vicinity of the loose end of the outermost electrode plates, so that the loose ends of the outermost electrode plates are securely held, as well as the bottom end face of the electrode plate group is duly protected by the tape.
While novel features of the invention are set forth in the preceding, the invention, both as to organization and content, can be further understood and appreciated, along with other objects and features thereof, from the following detailed description and examples when taken in conjunction with the attached drawings.